Method of making bas-reliefs



B. DIEFENBACH METHOD OF MAKING BAS RELIEFS F1106 April 4, 1924 PatentedMar. 31, 1925.

UNITED STATES PATENT OFFICE.

or BUFFALO, neon AND JAMES D. CAMPBELL, on

NEW YORK, BUFFALO, NEW YORK, A PARTNERSHIP, DOING BUSINESS UNDER THEFIRM NAME OF BUFFALO EV'ERLASTING DISPLAY COM- IPAN Y.

METHOD or MAKING IRAS-BELIEFS.

Application filed April 4, 1924. Serial No. 704,273.

To all whom it may concern:

Be it known that I, BERNHARD DIEFEN- BACH, a citizen of the Republic ofGermany, who has signified his intention of becom- 6 ing a citizen ofthe United States, residing at Buffalo, in the county of Erie and Stateof New York, have invented new and useful Improvements in Methods ofMaking Bas-Reliefs, of which the following is a 10 specification.

The object of the invention isto enable portions of one side of a plateof glass, metal and other material, to be removed by the action of asand blast in such manner as to economically and rapidly produce ahas-relief of more or less intricate design.

A particular objectis to enable portions of one of the layers of a sheetof cameo glass to be quickly,

removed by a sand blast, in such manner as to convert the sheet into acameo having any desired design and adapted to be used for variouspurposes, and particularly as an advertising sign, which is clearlylegible either by reflected light, or by light transmitted through thecameo.

This object is attainedby the improved method hereinafter described andclaimed.

f the accompanying drawings forming a part of this specification,

Figure 1 shows in perspective, a portion of a sheet of'cameo glass.

Figure 2 is section on line 2-2 of Figure 1. I

Figure 3 is a view similar to Figure 1, showing a coating of sensitizedpaste formed on one of the layers of the glass.

Figure 4 is a sectiononline 44 of Figure 3. e

Figure 5 isa side view; and

accurately and economically.

' form a letter 17,

Figure 6 an edge view of a portion of th I Figure 13 is a view similarto Figure 12,

showing the completed bas-relief after the removal of the hardenedportions of the sensitized coating."

The same reference characters indicate the same parts in all of thefigures.

In practising the improved method, as illustrated by Figures 1 to 10, asheet of cameo glass is treated as next described, the sheet being ofso-called flash glass, and including a body layer 12, preferably of opalglass, and a facing layer 13 of lass of any desired color, flashed onthe ody layer, the color of the facing layer contrasting with that ofthe body layer. One of the layers, preferably the facing layer,isprovided with a coating 14, of sensitized paste, which is adherent toglass, is quickly soluble, and is adapted to be rendered more slowlysoluble by the action of light.

To the coating 14 is applied a pattern composed of a sheet 15 of thinpaper, or other b ht-transmitting material, and a design ormed thereonby India ink, or other material, which is subsequently opaque when aplied to the sheet. In the example here s own, the opaque material isdesignated by 16, and is arranged to and border being onlight-transmitting portions of the sheet. 4

The design may be of any desired character, and may be more or lessintricate. The pattern ispreferably caused to adhere to {he coating 14by the adhesiveness of the atter.

and a border 18, said letter The assemblage as shown in section by IFigure 7, is next'subjected to the action of light, either s'olar Urartificial, the direction of the light being as indicated by the arrow m(Figure 7). 'The light passing through the light-transmitting portlons'of the pattern hardens the portions of the sensitized coating notprotected by the opaque portions of the pattern, the portions of thecoating thus protected being quickly soluble-by a solvent such as coldwater. The lighthardened portions of the coating are in v soluble incold water, and are solubl gin a different solvent, as, hereinafterdescribed. For convenience, I call these portions the hardened portionsof the coating, and the others the quickly soluble portions.

The pattern and the quickly soluble portions of the coating are nextremoved'by washing, and preferably by submerging the entire assemblagein a bath of cold water, until the pattern is detached and the saidsoluble portions are dissolved.

A sand blast is then directed, in the direction indicated by. the arrow3 in Figure 8, against the now partially protected glass layer and thehardened portions of the coating 14 remaining thereon, until the exposedportions of said layer are removed and the corresponding portions of theother layer denuded, as shown by Figure 9, other portions of thepartially protected glass layer being left intact.

The glass is thus converted into a cameo having relief portions 17 and18, corresponding to the portions 17 and 18 of the pattern, as indicatedby Figure 10.

After the application of the sand blast, the hardened portions of thecoating may be remoyed, in any suitable manner, as by immersing theassemblage in a bath of hot water containing ammonia, this bathconstituting a solvent of the hardened portions of the coating, which isthus dissolved and removed.

It isobvious that either of the glass layers may be the layer which isacted onby the sand blast. The sensitized paste may be composed of.bichromate of potash, two parts, glycerine seven parts, glue twenty.

ve parts, and water sixty-six parts.

The invention may be practised in making low relief opaque platessultable for signs and other purposes. 'For example, the sen- I Isitized coating 14 may be applied to one side light through the patternof a brass sign plate 20 (Figures 11, 12 and 13). After the exposure ofthe coating to 15, the pattern and the quickly soluble portions of thecoating are removed as above described, and the portions of theplatethus exposed are subjected to the action of a sand blast untildepressions 21 of the desired depth are formed and the plate becomes ahas-relief, after which the hardened portions of the coating are removedas before. The plate 20 may be of any material capable of being cut by asand blast.'

The method may therefore be practised in making a sign or ofher articlewhich is -a cameo adapted to transmit light and differently color thetransmitted light, or is an opaque relief plate. ,It is obvious that,the

pattern may be provided in any suitable way 4 with light-transmittingportions and opaque relief having depressions of considerable portions.

"It is essential for the production of a basexposed side 7 posed surfaceof said coating,

depth, and conforming accurately to the patside of the plate facing thesource of light, so that the light impinges directly on the exposedouter side of the coating, and its hardening actionis uniform from sideto side of the coating. The hardened portions of the coating are thuscaused to conform accurately to the pattern at each side of the coating,so that the design produced by erosion on the plate also conformsaccurately' to the pattern, and is not distorted or changed, as would bethe case if the pattern were applied to the side of a glass plateopposite the side having the coating. I

I am aware that it has been heretofore proposed to apply a sensitizedcoating to one side of a glass plate, and a pattern having opaque andlight transmitting portions to the opposite side of the plate, and outof contact with the coating; the light which 1 portions of the coatingare enlarged, and the quickly soluble portions correspondingly reduced,in area. Moreover the said plate must be wholly of clear,light-transmitting glass,.-and cannot be either a plate of cameo glass,including a layer which intercepts light, or a wholly opaque metal plate20.

My improvement is characterized first by the fact that the pattern isapplied to the of the coating 14, and secondly, by the fact that thelight rays are directed against the exposed side of the pattern, and donot pass through the plate, so that the hardened portions of the coatingenable the sand blast to accurately reproduce the design of the patternin the form of depressions of uniform depth, in the coated surface ofthe plate.

What I claim is:

1 The herein deseribedimprovement in the method of making a has-relief,which comprises applying a sensitized coating to a plate, positioning apattern having lighttransmitting and opaque portions adjacent theexposedsurface of the sensitized coating, directing-light onto saidcoating through the attern, removing the portions of the coatlng whichare not affected by the light. and erroding by a sand blast the portionv of the plate surface from which said coating has been removed. A

2. The herein described improvement in the method of making a has-reliefwhich comprises applying a sensitized coating to one of the layers of acameo-glass plate, positioning a pattern having light transmitting andopaque portions adjacent the exdirecting light onte the zit-t rn andpertions of said writing 1 exposed t erethr'ough, removing the portionsof the coating'which are not afiected by the light, and cutting throughthe layers of the I 5 plate to which theeoetin'g is appliedin conformitywith thenutlines off the. portions from which the coatinghas beenremoved,

, a 10 affixed 'my- '-i BERNHARD DIEFENBACH'.

